I just got a new 64 GB iPhone 5. I left it connected to my MacBook Pro all night last night via the USB cable. It's only about 85 percent charged.
Is that normal? Seems like it should be charged up by now.
No this is not normal.
An iPhone should not be using so much power overnight that a normal charge source cannot top it off in 4 hours.
The problems could be:
You can rule out the first by connecting the phone to charge and then powering it off. It will charge safely when powered off as the charge circuitry doesn't need the phone to be running.
The second problem might be a used up battery, a prematurely failing battery, damage to the internal charging circuitry.
The third problem could be as simple as the Mac not charging during hibernation (it would charge during sleep at 500mA level) or a bad cable or faulty port power. You can rule that out by charging from a proper wall adapter.
My salesperson told me to use my iPad's charger to charge my iPhone. Because of the higher wattage it charges pretty quickly, in a matter of hours.
That does sound very slow. Perhaps your MacBook Pro went to sleep after a period of no use, causing the charging to stop? How quickly does the phone charge while you're using your laptop?
Your Macbook most likely went to sleep. When any computer goes to sleep, it will stop all connections through USB and Wifi and so on.